How to load assets from external css frameworks?

I am having trouble loading fonts and images from an npm package providing css files, fonts, and images (Blueprint.js). My understanding is that if I

import '@blueprintjs/core/dist/blueprint.css'

in some js file, the css file will be included in the browser bundle. But apparently assets are not, as I am seeing errors like Failed to decode downloaded font in the browser console and no images show up as well.

What am I missing here?